The improved system of the present invention fundamentally comprises: a parison mold of the type which is divided or separated in two halves and which is suitably supported on its respective opening and closing mechanism, wherein the preform or parison is formed by the blowing of a gob of molten glass; an inversion arm to carry the preform from an inverted to a normal or upstanding position and vice versa to an inverted position; a crown mold mounted on the inversion arm, said crown mold being of the type which is divided or split in two halves and having a counterblowing nozzle and a retractable plunger or piston centrally disposed therein which is engagingly coupled to the lower half of the parison mold when both of its halves are closed to form the crown, thereby reducing the time for mechanical movement through the combination of a funnel, centrally and coincidentally integrated to the upper part of the parison mold, to receive, guide and/or pre-form a gob of molten glass to the inside of the parison mold; a compression head that engages and disengages, by means of its inlet and outlet devices, respectively, with the integral funnel, to provide a seating blowing action which seats the gob at the bottom of the parison mold, to ensure the filling of the crown mold for the proper crown formation and guarantees the uniform contact of glass with the parison mold walls; a closure or baffle that has its lower, internal part shaped to conform with the bottom of the preform and which is engaged and disengaged, alternately with the compression head and through its respective inlet and outlet devices, with the integrated funnel and which has as its sole purpose the closing of the upper part of the parison mold, to enable the counterblowing by the crown mold, to inflate the gob and form the preform by means of which mechanical movement time is reduced by reducing each stage of the operation, thus permitting better quality and/or greater production of glassware.
I. Field of the Invention
In the conventional system for glass container production by the so-called "blow-blow" process in I.S. machines with Individual Sections for blowing glass articles, it is necessary to form a preform or parison in an inverted position, in which the container crown is also formed, and then the preform is inverted to its normal position and is deposited in the finishing mold, in which it is blown by filling the finish mold, thus shaping the container to the desired final shape.
Preform formation for glass container production is conventionally carried out by means of the blow-blow process and in the I.S. machines by first coupling a funnel over the parison mold, to receive, guide and/or pre-form the molten-glass gob which is usually cylindrical in shape and supply it centrally to the parison mold; thereafter there is coupled over the funnel, a closure that provides a settle blowing that settles or seats the gob in the bottom of the parison mold, in order to fill the crown mold, correctly shape the container crown and allow for uniform contact of glass with the parison mold walls. After performing the seating blowing, the closure is disengaged and withdrawn and the funnel is disengaged and withdrawn. Finally, the closure is again engaged, this time over the parison mold, to act in this instance, as a closure that has the shape of the preform bottom, to perform the counterblowing and shape said preform.
In a timed sequence, the conventional system for forming the preform includes: one crown forming time during which the funnel is engaged over the parison mold, one gob of molten glass is loaded into the parison mold and the closure is engaged over the funnel to provide the settle blowing that ensures filling of crown mold and the formation of the crown in the preform; then, there is a movement time period during which the glass gob remains inside the parison mold while the closure is being engaged and disengaged, the funnel is engaged and disengaged and the closure is again engaged, this time over the parison mold to act solely as a closure; finally, there is a counterblowing time wherein the preform is inflated and shaped inside the parison mold, leaving said preform ready for inversion and final blowing in the finish mold. In glass container production with conventional I.S. machines and with the blow-blow process, there normally results a limited number of finished containers containing a flaw known in the art as settle wave. The settle wave is a thinned glass ring that extends around the blown container in the area between the container bottom and approximately three-fourths of its height and is due to a non-uniform glass distribution on the container walls. The settle wave and non-uniform container walls produce a reduction in the container strength, and thus, these containers leave much to be desired as to quality. It has been found that product quality can be considerably improved when the counterblowing time is increased, since this allows for good blowing or inflation of the preform and, consequently, a good glass distribution on container walls. Now, since both the crown formation time and the total preform formation time are considered as constant for a given type of container, the counterblowing time could be extended only at the expense of mechanical movement time. However, in conventional I.S. machines it is practically impossible to reduce the time for mechanical movement since it is absolutely necessary to disengage and remove the closure from the funnel, disengage and remove the funnel and again engage the closure, this time over the parison mold, which is a time-consuming operation. On the other hand, it is practically impossible to speed up the closure and funnel engagement and disengagement to reduce the time for mechanical movement since there exists a necessary time index therefor, due to friction between the parts. Additionally, the known I.S. machines have the disadvantage that the closure operates twice in the same forming cycle, first to provide a settle blowing and then as a closure, thus resulting in more work that will wear its mechanism at a faster rate.
Due to these problems, in-depth studies have been carried out for the purpose of reducing the time duration for mechanical movement in order to prevent flaws in the containers and reduce the operation of devices to a minimum to prevent excessive wear thereof.
II. Description of the Prior Art
U.S. Pat. No. 3,536,468 claims an apparatus to perform the glass parison forming with a seating blowing closing means that comprises, in a single unit, a funnel to receive and guide the glass gob, coincidently engaged over a seating blowing and lubricant spray device, that allows lubricant spray inside the parison mold or outside the glass gob passing therethrough and the immediate application of the seating blowing without mechanical funnel and closure replacement that provide the seating blowing. The seating blowing and lubricant spray device consists of: one seating blowing valve comprising a valve shell connected with a line that provides for the seating blowing; an internal frame concentrically secured inside the shell and provided with horizontal, diametral openings for the passage of the seating blowing therethrough and a pair of swinging gates that drop by gravity onto the substantially quadrangular hollow in the frame, covering the openings thereof; said gates, upon action of the seating blowing will lift up and cover the entrance of this valve, thus allowing to carry out the seating blowing without the same escaping through the valve and funnel, and a lubrication valve coupled under the seating blowing valve, which consists of a valve shell connected with a lubricant-supply line and an annular nozzle concentrically located inside the valve shell, having the shape of a secondary nozzle to receive, lubricate and correct the path for the gob coming from the quadrangular space in the seating blowing valve frame and said lubrication valve is coupled to the upper part of the parison mold. Thus, with said apparatus the need of engaging and disengaging the funnel in the usual sequence is avoided, since the funnel is already coupled as a unit on the seating blowing device; thus, this device will only be engaged to perform the guidance, lubrication and seating blowing in a single operation and thereafter to withdraw and engage the bottom closure, to carry out the counter blowing, shape the preform and thus, try to reduce the mechanical movement time. Although this apparatus has the advantage that the funnel is coupled with the seating blowing and lubricant spray device as a unit, that is engaged over the parison mold, to then engage the closure and perform the counter blowing in only two operations, it has the considerable inconvenience that the device is too heavy and cumbersome for quick movement, requiring a mechanical movement time, that is perhaps, even greater than that of conventional machines, since the components of the latter are much lighter and expedient to remove.
Likewise, due to the weight and bulk of this apparatus, serious wear problems occur in the machine.
Said apparatus also has the disadvantage that it has reduced operational efficiency, since the closing gates to perform the seating blowing, leave much to be desired in their operation and the equipment sealing. On the other hand, the apparatus is somewhat complicated in its construction, operation and maintenance, making it very costly.
U.S. Pat. No. 3,672,860 claims an apparatus similar to that of U.S. Pat. No. 3,536,468, with the difference that the former includes a lubricant spray nozzle that is shaped in a fashion to adapt to a non-circular section preform, in order to pre-mold the glass gob to produce non-circular section preforms and containers and that also includes all the disadvantages inherent to the apparatus.
U.S. Pat. No. 3,171,128 discloses an apparatus that suggests, without claiming the same, the advantage that the upper part of the parison mold is shaped as a funnel for glass-gob-reception and guidance; however, this apparatus is completely different from that of the present invention since, in lieu of performing a seating blowing through the upper part of the parison mold, to ensure good glass contact with the parison-mold walls, a vacuum is drawn through the crown mold part and, then, only a parison-bottom closure is engaged to perform the counter blowing. Said apparatus has the disadvantage that, by substituting crown vacuum for the seating blowing, uniform glass contact with the parison-mold walls is not ensured and is subject to glass trapping air bubbles between the glass and the parison-mold walls which, upon counter blowing the gob will prevent uniform glass distribution on the preform walls, the settle wave appearing again and, consequently, will bring about the formation of poor-quality containers.
Finally, in the publication Glass Technology, Vol. 9, No. 6, of December 1978, there is described the concept of integrating the funnel with the parison mold and conform the closure to them, comprising a machine which is completely different from the I.S. machine, since it operates with the press-blow process.
In other words, heretofore, a reduction in the mechanical movement time in the I.S. machines had not been achieved, since the same operates with the blow-blow process, in a simple and economical manner.